Sahih Muslim Book - 33, Hadith - 4788

وَحَدَّثَنِى زُهَيْرُ بْنُ حَرْبٍ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِىٍّ حَدَّثَنَا مَهْدِىُّ بْنُ مَيْمُونٍ عَنْ غَيْلاَنَ بْنِ جَرِيرٍ عَنْ زِيَادِ بْنِ رِيَاحٍ عَنْ أَبِى هُرَيْرَةَ قَالَ قَالَ رَسُولُ اللَّهِ -صلى الله عليه وسلم- « مَنْ خَرَجَ مِنَ الطَّاعَةِ وَفَارَقَ الْجَمَاعَةَ ثُمَّ مَاتَ مَاتَ مِيتَةً جَاهِلِيَّةً وَمَنْ قُتِلَ تَحْتَ رَايَةٍ عُمِّيَّةٍ يَغْضَبُ لِلْعَصَبَةِ وَيُقَاتِلُ لِلْعَصَبَةِ فَلَيْسَ مِنْ أُمَّتِى وَمَنْ خَرَجَ مِنْ أُمَّتِى عَلَى أُمَّتِى يَضْرِبُ بَرَّهَا وَفَاجِرَهَا لاَ يَتَحَاشَ مِنْ مُؤْمِنِهَا وَلاَ يَفِى بِذِى عَهْدِهَا فَلَيْسَ مِنِّى ».

It was narrated that Abu Hurairah said: "The Messenger of Allah (s.a.w) said: 'Whoever rebels against obedience and separates from the main body of Muslims, then dies (in that state), has died a death of Jahiliyyah. Whoever is killed (fighting) for no real cause, getting angry for the sake of tribalism or fighting for tribalism, is not of my Ummah. Whoever of my Ummah rebels against my Ummah, striking righteous and wicked alike, and does not spare the believers and does not pay attention to anyone who has a covenant of protection with the Muslims, he is not of me."